marstair beer cellar unit

[airconadam]

hey fellas long time since i posted but here it goes. Went to a unit today marstair (ckc80) not working/cooling, when i checked the at the outdoor and removed the covers i noticed the start capacitor had a completly burnt cable and now making no connection:eek: when i looked at it it was the neutral wire what went to the neutral block and then the other cable then went to the start winding on the compressor.What i wanted to know is what has caused this i checked the compressor down to earth but it seemed all ok i also phoned marstair but they didnt seem much help,he just said it sounds like you got a short in the capacitor any help much appreciated thanks alot

adam:D

[Kp3]

hi
poss short or lose connection.
did you check amps on comp both start up and running amps?
was the relay ok?

[airconadam]

kp3 the comp wouldnt start or run i pressumed because of the capacitor but i dont really understand capacitors to tell you the truth thanks alot

adam

[Kp3]

that is correct if capacitor has gone it wont start.
capacitors are a storage of electicity to help start or run the comps more smoothly
hope this helps

[airconadam]

excellent kp3 abit like a soft start then for the compressor? thanks alot hopefully a new capacitor should sort the problem

adam

[Kp3]

thats poss but do check the amps and relay
take it easy

[coolments]

Hi Adam

Many things could have caused that but to help you understand capacitors see discription fo you below, 3 types to look at. (knicked this next bit from else where to save me typing it up.)

Capacitor Start-Induction Run (CSIR)

The CSIR motor is similar to the RSIR except a start capacitor is included in series with the start winding to produce a higher starting torque. This is commonly used on commercial refrigeration systems through 3/4HP. Two types of relays are used with this motor:
 A current relay, or
 A potential relay


Capacitor Start and Run (CSR)

This motor arrangement uses a start capacitor and a run capacitor in parallel with each other and in series with the motor start winding. This motor has high starting torque, runs efficiently, and is used on many refrigeration and air conditioning applications through 5HP. A potential relay removes the start capacitor from the circuit after the motor is up to speed. This motor may use either:
 An external thermal protector, or
 An internal thermal protector.


Permanent Split Capacitor (PSC)

Here a run capacitor is in series with the start winding. Both run capacitor and start winding remain in the circuit during start and after motor is up to speed. This normal starting torque motor is sufficient for capillary and other self-equalizing systems. No start capacitor or relay is necessary. For additional starting torque, a proper start assist kit may be added. Some start assist kits may include:
 A wired-in Positive Temperature Coefficient (PTC) relay, or
 A module Positive Temperature Coefficient (PTC) relay

(back to me) easy way to test the capacitor, use the following method.

A capaciotor basically kicks the compressor into life much like a starter motor would start your van, the duty is measured in microfarad or μμF symbol, look on the capacitor and find the number before the sysmbol, look for the same symbol on your tester(on most multimeters if not get one that has), take the wires of the capacitor and ark the terminals of the cap with an insulated screw driver across them to make sure its discharged. then connect the tester and get a reading. to find if the capacitor is ok it should read the same number on the tester as written on the capacitor with +or - a % that is also wrote on the capacitor.
A lot of compressors get reported as seized due to most engineers ignoring capacitors.

Got a drawing for you also, hope it helps.

[airconadam]

hey coolments i do remember learning about them at college but there is so much to take in:rolleyes: reading through that i would say this system has a psc capacitor and not a start capacitor as there was only one capacitor in the circuit. I think iwill check the capacitor out as you described,I can see how people do say compressors have gone because that was my thought at first but i dont like just jumping at things thanks alot

adam:D

[Brian_UK]

Marstairs (IMI) often had electrical failures due to the cable terminations not being up to scratch.

Crimp terminal would corrode or have loose crimp on cable and slowly overheat, either burning out the cable or whatever was connected to it.

I used to call them the "Friday" units.

edit: Sorry, forgot to add, if you want a Tech manual for that unit you can download one from here..
http://www.marstair.com/manuals-brochures.php

[airconadam]

Thanks for the link brian will have a good look through:D

adam:D